1. Field of the Invention
The present invention relates to a starting clutch which can be used in place of a torque converter in a motor vehicle or the like.
2. Related Background Art
FIG. 2 is an axial sectional view of a conventional starting clutch. Now, a conventional technique will be described with reference to FIG. 2. A starting clutch 100 includes a multi-plate clutch 101. Within a clutch case 106 of the multi-plate clutch 101, friction plates 102 which are output side friction engaging elements, and separator plates 103 and a backing plate 104, which are input side friction engaging elements, are alternately arranged. A left side (in FIG. 2) of the backing plate 104 is supported by a stop ring 105. At a right side of the friction engaging elements, there is disposed a piston 108 arranged within the clutch case 106 with an O-ring 107 therebetween. The piston is biased toward the right (in FIG. 2) by a return spring 116 so that the friction engaging elements are normally brought to a non-engaged condition. Further, an oil chamber 109 is defined between the piston 108 and the clutch case 106.
The starting clutch 100 comprises the multi-plate clutch 101 having the above-mentioned arrangement, a housing 110 covering an outer periphery of the multi-plate clutch 101, and a damper 117 disposed between the clutch case 106 and the housing 110. The housing 110 is connected to an output shaft 111 of an engine (not shown). A retainer plate 113 is disposed in the damper 117. The retainer plate 113 holds a spring 130 and is attached to an outer periphery of the clutch case 106. A pawl portion 114 elastically engages the spring 130 and is secured to an inner wall of the housing 110.
When oil pressure is supplied to the oil chamber 109 through an oil passage for supplying oil to the starting clutch 100, the piston 108 is operated to achieve a friction engaging condition.
However, in the conventional starting clutch, since the retainer plate 113 for holding the spring 130 is a relatively heavy member and is attached to the outer periphery of the clutch case 106, a weight of a clutch side portion of a wet type multi-plate clutch is increased. Thus, a bearing having a relatively great size must be used and a wider attachment space must be reserved accordingly. Further, since an oil passage for supplying cooling oil to the wet type clutch is formed in the shaft, a disadvantageous condition regarding strength occurs.
Accordingly, an object of the present invention is to provide a starting clutch which is compact and in which a weight of a clutch side portion is reduced and a disadvantageous condition regarding strength is eliminated.
To achieve the above object, the present invention provides a starting clutch comprising a wet type multi-plate clutch having a clutch case, a housing attached to an output shaft of an engine and adapted to cover the wet type multi-plate clutch, and a damper disposed between the wet type multi-plate clutch and the housing, and wherein the damper is constituted by a spring, a retainer plate for holding the spring, and a pawl portion elastically engaging the spring, and the retainer plate is attached to the housing and the pawl portion is attached to the clutch case. Further, in the starting clutch, the pawl portion may be spline-connected to the clutch case.
Among the structural elements of the damper, the retainer plate for holding the spring may be attached to an inner wall of the housing, and the pawl portion may be attached to outer periphery of the clutch case by spline fitting. In this way, a weight acting on the clutch side can be reduced.